Setts



Sept. 6, 1932.

c. H. EGAN ET AL 1,876,450

SELF TIGHTENING CONTAINER CLOSURE Filed-Dec. 17; 1927 4/1): all, "lie-age? W@AZMW malted Sept. 6, 1932 UNITED STATES PATENT oFFlcE CEABUFS H. EGAN, OI BOSTON, AND BRADLEY DEWEY, OF CAMBRIDGE, MASSACHU- SE'ITS, ASSIGNORS TO DEWEY AND ALHY CHEMICAL COMPANY, OF CAMBRIDGE,

MASSACHUSETTS, A CORPORATION 01 MASSACHUSETTS v SELF-TIGHTENING CONTAINER CLOSURE Application filed December 17, 1927. Serial No. 240,756.

Our invention relates to closures for containers, and is characterized by a novel and useful relationship between the containermembers (e. g., vessel and cover) which in I? juxtaposition provide confining walls of a seam-space, and the material confined in such sealm-space as a' sealing or caulking mater1a The efliciency of a container closure is conditioned by the relationship of the sealing material to the contents of the container. If the contents consist of or comprise a material which is sufficiently fluid to insinuate itself into the sealed seam, and which acts upon the sealing material in the seam to disintegrate the same, loss of sealing efliciency is only a question of time. Many containers, such as cans, are sold without knowl edge on the part of their maker of the materials which will be stored in them; if, for instance, the sealing material provided be immune to water but not to oils, and the cans be used to contain oily material, the final result will be unsatisfactory.

Our invention herein described, is concerned with the relationship of colloidal mutual extension as between the more or less fluid contents of a container and the seal substances, and with-means for controlling the effects of such mutual extension. The

seal substances are in substantially solid condition in the seal. If, of several ingredients in the container closure seal, confined closely in a sealing seam, one at least is unsusceptible of gel formation with the fluid contents of p the container, its presence, cooperating with the physical confinement of the seal material by the container-members, will check and control the progress of other component or components toward sol formation, if one or more of such be susceptible of gel and sol formation with the said contents. Thus, a

container closure depending on rubber as a cardinal ingredient, while reliable and durable to hold can contents comprising water or the common alcohols or ketones, will deteriorate if the container is filled with material containing oils, or typical solvents of rubber such as benzol, naphtha, carbon tetrachloride, etc, whereas some sealing materials which are susceptible to water or the common alcohols or ketones would retain can contents comprising ingredients which attack rubber. As a very large proportion of materials habitually stored in sealed containers have either a water or an oil base, it is desirable to furnish a container closure which is, by its composition, inherently able to resist or compensate for the deteriorating action of such contents.

The drawing hereto annexed illustrates, in much enlarged cross section, the seam joint between a can and its head. In this drawing, B represents part of the can body, T part of the can top, and S a sealing composition, originally deposited in an annular peripheral channel of the can top, and tightly confined between the two container-members in the seam formed by double-rolling the edges thereof together, in the manner shown. Such containers constitute probably the most conspicuous example of containers comprising closely juxtaposed body and cover members, forming a confined seam-space for the retention of sealing material; other and analogous examples are furnished by bottle caps and the like, held to the container by pressure.

Further exemplification of our invention is as follows: Attach to one of the members of a container, either the body or cover, a sealing material, containing approximately equal quantities of rubber, and either or both of the other following named materials:

(1)v A rubber, which is insoluble, in, or not forming a gel with, water, or with alcohols or ketones. Y

(2) A substance insoluble in, or not forming a gel with, oils, or common rubber solventsvor with alcohols or ketones.

(3) A substance insoluble in, or not form-' I can be applied is limited by the size of the' the oil (or common rubber solvent) unsusceptible, and/or common alcohol (or ketone) unsusceptible, and the rubber components dissolved or dispersed therein, and the composition thus deposited is dried, and the container closure is then ready for the sealing operation.

i It is obvious that the amount of fluid which such as glycerin, invert sugars, diethylene glycol, etc., which keep the dried seals from becoming brittle.

The container closure, completed by attachment of the body and cover, as by doubleseaminga can head to a can body, or by evacuating a jar and fixing a cover thereon by atmospheric pressure or otherwise, tightly confines the above-described sealing material in the seal joint, and so long as the sealing material remains tightly confined in said joint, the contents of the can or other container will be adequately protected. If the canner uses cans or containers thus sealed to hold materials comprising an oil, the oil-susceptible rubber particles contained in the seal, when'seleetively attacked by, the contents, start to swell, be attacked, that is, to form a gel, or dissolve; but the oil-unsusceptible ingredient, intimately associated with the oilsusceptible ingredient, being unsusceptible to the can contents, retards and eventually restrains the swelling or solution, and prevents the swelling or solution action from extruding the seal material from the space within whichthe closure confines it. If the same container is used for material having a water base, the 'water-unsusceptible rubber ingredient functions as the restraining factor and prevents the initial alteration of the water-susceptible ingredient from proceeding to'adegree damaging to the integritv of the seal as a whole. The restrained swelling action, either case, operates to tighten the sealing material in the container closure, so that the container closure is self-tightening in either emergency. If with rubber there be compounded a material which forms a gel with alcohol or a ketone, with which rubber doesnot form a gel, the closure which comprises within its seam-walls such a composition with rubber will be self-tightening in the presence of alcohol or ketone contents of the container, the rubber acting as the sustaining factor when the alcohol or ketone gelforming constituent starts to swell and disintegrate.

And likewise, if with rubber there be com,- pounded a water-gel former and an alcoholgel'former, either rubber solvents, water, or alcohol, etc., may be safely placed in the container, since the restraining factor is provided for each alternative.

When using water as the initial vehicle, we

prefer to make these compounds by making a solution, with or without heat, of the watersoluble ingredient, in a portion of the water to be used. Preservatives may be added" during this solution. We then make an artificial dispersion, if a natural dispersion is not used, of the insoluble ingredient in the balance of the water, by grinding it in a pebble mill or in one of the ordinary types of colloid mills with water, and, if desired, one or more protective colloids together with such alkaline or acid bodies as may aid to stabilize the resultant suspension. The solution and the dispersion, together with any desired fillers and softeners, are then mixed by stirring,

with or without heat; If desired, the fillers may be mixed with the insoluble constituent before grinding. Our invention may be visualized by considering that where oil is brought into contact with rubber or other similar'colloids, the first thing to happen is an absorption of the oil by such colrloids, and that when water is brought into contact with solid glue or other similar colloids, the first thing to happen is an absorption of the waterby such colloids. The absorption in either 'case continues until a very marked swelling has taken place, until which time there is no solution of the rubber-like products into the oil or of the glue-like products into the water.

These properties are both well recognized, and

gredient which is being attacked by the contents of the container. This action is reinforced and made even more effective because of the fact that as the solvent penetrates the III sealing material the ,attacked ingredients swell and are thereby even more firmly bound within the network and within the confined space between the walls. Thus/in coaction with the confinement by the seam space walls this swelling tightens the seal and makes it much more diflicult for the contents of the container to get through from the interior of the container and attack further the sealing material. The relative proportions of the mutually distributed rubber-like and gluelike ingredients may 'be varied, but it is absolutelyne'cessary to have in the sealing material an effectively substantial proportion of each ingredient. A preferred mixture is one having rubber and glue in approximately the same proportions, and the following are examples of good workable formulae for sealing material which will confer self-tightening capacity upon the container closure.

(1) Bentonite 2 parts, gum karaya 0.4 part, sodium fluoride 0.15 part, water, including that of the rubber latex, 81.75 parts, sodium carbonate 0.24 part, ammonia 1 part, animal glue 7.23 parts, rubber, as rubber latex, 7.23 parts.

(2) Bentonite 2 parts, gum karaya 0.4 part, sodiumfluoride 0.15 part, water, including that of the rubber latex, 78.85 parts, sodium carbonate 0.24 part, ammonia 1 part, glycerin 2.9 parts, animal glue 7.23 parts, rubber, as rubber latex, 7.23 parts. A

(3) Bentonite 2 parts, gum karaya 0.4 part, sodium fluoride 0.15 part, water, including that of the rubber latex, 73.04 parts, sodium carbonate 0.24 part, ammonia 1 part, glycerin 2.9 parts, animal glue 7.23 parts, rubber, as rubber latex, 7.23 parts, whiting 5.81 parts.

In the above-scheduled examples of selftightening sealing compounds, the glue in (1), (2), and (3) exemplifies the water-gel forming, 'or water-soluble factor; the latexrubber in (1), (2) and (3), exemplifies the oilor common rubber solvent-gel-forming factor.

The other ingredients named are supplemental; bentonite, karaya gum with sodium,

carbonate, ammonia. for alkaline reaction constitute as a group a filling, dispersion-stabilizing factor; whiting is a convenient filler;

gel formation with water, the rubber and gel forming substance being in such substantial proportions that each, while in confinement between said walls, shall furnish effective restraint against substantial removal of the other by substances which are normally capable of accomplishing such removal.

2. A sealed container comprising a sealed joint including spaced walls and a sealing material confined between said walls, said sealing material comprising,-in its operative condition, a substantially homogeneous mixture including rubber and glue, the rubber and glue being in such relative proportions that each, while in confinement between said walls, shall furnish effective restraint against substantial removal of the other by substances which are normally capable of accomplishing such removal.

3. A container comprising a sealed joint including spaced walls and a sealing material confined between said walls, said material, when in operative condition between said walls, being substantially homogeneous in structural consistency and including rubber and asubstance capable of gel formation with water, the rubber and gel forming substance being in approximately equal proportions.

Signed by us at Cambridge, Massachusetts,

this 14th day of December 1927.

CHARLES H. EGAN.

BRADLEY DEWEY.

sodium fluoride is a preservative; glycerin a.

softener.

It will be evident to those skilled. in the art that these are but samples'of mixtures that will provide a self-tightening closure such as has been described, and that the essential feature is the use with rubber of a constituent unafiected by rubber solvents but susceptible to solvents to which rubber is indiflferent. For the sake of brevity, we prefer to describe these constituents as constituents capable or incapable of gel formation, irrespective of whetherthe attack or solvent action tends to form a gel within the narrow meaning of the word; i. e. if it forms a colloidal solution.

We claim:

1. A sealed container comprising a sealed joint including spaced walls anda sealing material confined between said walls, said sealing material comprising, in its operative condition, a substantially homogeneous mixture including rubber and a substance capable of 

